Auto merge of #13334 - nyurik:ascii-str-eq, r=xFrednet

Add manual_ignore_cast_cmp lint

```rust
// bad
fn compare(a: &str, b: &str) -> bool {
    a.to_ascii_lowercase() == b.to_ascii_lowercase()
    || a.to_ascii_lowercase() == "abc"
}

// good
fn compare(a: &str, b: &str) -> bool {
   a.eq_ignore_ascii_case(b)
   || a.eq_ignore_ascii_case("abc")
}
```

- [x] Followed [lint naming conventions][lint_naming]
- [x] Added passing UI tests (including committed `.stderr` file)
- [x] `cargo test` passes locally
- [x] Executed `cargo dev update_lints`
- [x] Added lint documentation
- [x] Run `cargo dev fmt`

changelog: New lint: [`manual_ignore_case_cmp`] `perf`
[#13334](https://github.com/rust-lang/rust-clippy/pull/13334)

Closes #13204

0 files changed, 0 insertions, 0 deletions